We request purchase of an integrated ultra-sensitive microbore liquid chromatograph-mass spectrometer with capabilities for electrospray ionization analysis of proteins and enzymatic digests of proteins. The instrument requested, a Finnigan LCQ Deca, is capable of mass spectral fragmentation and sequencing of peptides at sub-picomole to femtomole levels. Its presence in our existing MS Core Facility will add capabilities we currently lack to support the research programs of the PI and six other faculty with research programs which will be dramatically enhanced by the ability to attack problems which are currently not possible with existing equipment on campus. This instrument has the capability of analyzing and sequencing even mixtures of multiple peptide fragments that happen to co-elute on reversed-phase liquid chromatography. This will benefit a number of NIH-funded research programs dealing with a variety of health-related problems.